January 19, 20233 yr Hi all, I have purchased and been using 2 Securi-Prod Lithium Iron Phosphate Battery 12.8V 20AH with a Mecer inveter. The battery data sheet does not recommend that I run these batteries in a parallel-series connection. Does anyone have any idea why its not recommended. I am looking to purchase another 2 hence the question. https://www.iotrend.co.za/products/securi-prod-lithium-iron-phosphate-battery-12-8v-20ah Thanks!
January 19, 20233 yr 41 minutes ago, Ady_za said: Hi all, I have purchased and been using 2 Securi-Prod Lithium Iron Phosphate Battery 12.8V 20AH with a Mecer inveter. The battery data sheet does not recommend that I run these batteries in a parallel-series connection. Does anyone have any idea why its not recommended. I am looking to purchase another 2 hence the question. https://www.iotrend.co.za/products/securi-prod-lithium-iron-phosphate-battery-12-8v-20ah Thanks! If trying to think about it I would say series does have a negative but I fail to see why parallel is also not recommended.
January 19, 20233 yr Just as with lead, to have the batteries in series or parallel, you want them to be the same age/charge/brand/size etc so typically you buy two at once and use them. Otherwise you get one discharging at a different rate to the other, leading to extra stress on one of the batteries. For parallel connections, make sure that you wire them together and then put the positive of the first battery to the inverter and the negative of the second battery to the inverter. This will ensure that both batteries get used the same amount as the cable lengths and current path is the same for both. See picture HERE if I am not making sense. The lithium batteries all have some form of BMS, even if it is a simple comparator circuit so they will manage their charging just fine, regardless of series or parallel provided you remain within their charge/discharge spec. Edit: Just took a look at the datasheet. They even give you the correct wiring as described above. From what I have seen, almost every battery like that has the same warning - mostly BS to cover themselves IMO Edited January 19, 20233 yr by SteveP
January 19, 20233 yr Author Thanks Steve, I currently have them connected in parallel in order to double the voltage since my inverter is 24v. I want to add the other to 2 (exact same batteries) and connect them in series-parallel combination connection in order to maintain the 24v but add the extra 40ah. I'll buy the extra 2 anyway and test it out. Thanks tho.
January 19, 20233 yr If you want peace of mind - take a look at installing a "battery balancer" to manage the batteries in absence of a global BMS connected to the inverter. Also, just make sure you wire things up something like THIS to be sure of equal charge/discharge (even if using a battery balancer).
January 19, 20233 yr How big is the inverter? One thing you want to be mindful of is having batteries that are too small to provide the desired current as that will damage them.
January 19, 20233 yr Author Its the Mecer 2400VA (1440W) Inverter Battery Charger (UPS) - Intelligent Fan. Will it still be necessary to install a "battery balancer" using this inverter? Its being used to power small appliances around the house and not directly plugged into the db board. https://www.geewiz.co.za/mecer-inverters/5309-mecer-2400va-1440w-inverter-battery-charger-ups-intelligent-fan.html?sfdr_ptcid=2961_617_13175719&sfdr_hash=e9865a94ca7beb638cb8c3930e296aa0&gclid=Cj0KCQiA8aOeBhCWARIsANRFrQGngf8mKjeIEm1pAWMQUF1poEaWoiZqOyApWpYJjAzfsiJYPgXiYoYaAorXEALw_wcB
January 19, 20233 yr 5 minutes ago, Ady_za said: Its the Mecer 2400VA (1440W) Inverter Battery Charger (UPS) - Intelligent Fan. Will it still be necessary to install a "battery balancer" using this inverter? Its being used to power small appliances around the house and not directly plugged into the db board. https://www.geewiz.co.za/mecer-inverters/5309-mecer-2400va-1440w-inverter-battery-charger-ups-intelligent-fan.html?sfdr_ptcid=2961_617_13175719&sfdr_hash=e9865a94ca7beb638cb8c3930e296aa0&gclid=Cj0KCQiA8aOeBhCWARIsANRFrQGngf8mKjeIEm1pAWMQUF1poEaWoiZqOyApWpYJjAzfsiJYPgXiYoYaAorXEALw_wcB Your previous post mentioning being in parallel to get 24V is actually meant to be series. Parallel the voltage will stay 12V. Yes you will reap the rewards when using a balancer. Inverters cannot balance batteries that are connected in series. Or shall I say I have not seen one.
January 19, 20233 yr Author My mistake, they are connected in series. Alright thanks, do you have any balancer that you would recommend?
January 19, 20233 yr 6 minutes ago, Ady_za said: My mistake, they are connected in series. Alright thanks, do you have any balancer that you would recommend? HA02 with or without Bluetooth. Various sellers. Some are for 2 batteries and others for 4 batteries.
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